I am having a new trans put in the Van and the Dealer is telling me the tank in the radiator is not flowing enough, I watched them flush it then check it and I know the fluid that came out looked like driveway sealer. They checked it with a machine to see the GPM, gm specs 9 but we are below 6. Is there a chemical I can spray in there or do I need to replace the radiator? Can a radiator shop clean it out but removing the tanks? Radiator is not available for a few days and I need this thing to make money.

I take it that your radiator is a jobber, you can get a new radiator with a good cooler, or put on an fluid to air cooler, they cool OK but, in the winter they over cool. I personally would go with a new rad, and if they can't supply it, A decent rad shop can make you one. Or put on the air to fluid cooler till the new rad comes in.

I will just have to bypass it until I get the radiator I think. I will see tomorrow the exact time frame of the new radiator.
The problem is that if they don't submit the flow rate to GM there is no warranty on the trans they tell me.